Construction is underway on ContourGlobal’s Project Sterling, a solar-and-battery development in Mohave County, Arizona. Tesla is reported to have a long-term agreement to buy around 1 terawatt-hour (TWh) of electricity each year—about 90% of the project’s expected output—along with associated renewable energy certificates.
Project Sterling takes shape in Arizona
The site is about 20 miles north of Lake Havasu City. Its planned footprint exceeds 2,000 acres, with more than 760,000 solar modules and over 300 battery containers.
The project’s solar and battery scale
Project Sterling is rated for 509 megawatts (MW) of solar capacity on a direct-current (DC) basis and 450 MW on an alternating-current (AC) basis. DC describes the panels’ output before conversion; AC is the form used by the grid. The two ratings describe different points in the system.
The batteries are designed to store about 1.4 gigawatt-hours (GWh) of energy and discharge at up to 360 MW. MW measures power output; GWh measures stored energy. At the maximum rated output, 1.4 GWh corresponds to about 3.9 hours of discharge.
The planned battery system uses lithium iron phosphate (LFP) chemistry, liquid cooling and integrated fire protection.
What Tesla is reported to buy
A power purchase agreement (PPA) is a long-term contract for electricity. Tesla is reported to have a PPA covering around 1 TWh annually, plus associated renewable energy certificates. That volume is described as about 90% of Sterling’s expected generation.
The project is forecast to generate more than 1.1 TWh per year. One TWh equals 1,000 GWh, making the reported contract volume and the plant’s projected total distinct figures.
Arizona location and the route to California’s market
Project Sterling is located in Arizona. Its planned grid connection is to the Western Area Power Administration (WAPA), and the project is reported to have transmission rights into the California Independent System Operator (CAISO) market in California.
